Export toForest from the Decoder module

[camsjams]

🚀 Feature request

Current Behavior

Decoder works great! Decoder.draw is helpful but not useful when we need HTML form validation.

Desired Behavior

It would be a nice utility to expose Decoder.toForest for some extra hands-on control of error message manipulation.

Suggested Solution

Adjust the exports:

typescript
const toForest = (e: DecodeError): ReadonlyArray<Tree<string>> => {

To be:

typescript
export const toForest = (e: DecodeError): ReadonlyArray<Tree<string>> => {

Who does this impact? Who is this for?

This should not impact anyone AFAIK, since it just an additional exported member. This would make io-ts for html form validation messages much easier as we can utilize the toForest helper to do most of the lifting.

Describe alternatives you've considered

The current alternative that works for our system is to just copy->paste toForest and its related functions into our codebase.

Additional context

n/a

Your environment

Software	Version(s)
io-ts	2.2.16 (2.2+)
fp-ts	2.10.5
TypeScript	4.1.3

[gcanti]

@camsjams I wouldn't recommend using the Decoder.ts module in production, it's still experimental and I'm working on a new version (branch poc for a sneak peek)

[steida]

@gcanti It would be great if all errors would not be mandatory an opaque string, so we could use exhaustive check without additional wrappers or hacks.

[steida]

@gcanti Do you plan big changes? I just started using experimental API. I'm OK with refactoring.

[gcanti]

@steida for the error model? yes. I'll write a summary of my findings in #453 as soon as possible